Package sulfur plant

ABSTRACT

A COMPACT APPARATUS FREE FROM EXTERNAL PIPING IS DESCRIBED HAVING WITHIN A SINGLE ELONGATED SHELL A BOILER AND CONDENSER SECTIONS WITHIN A SINGLE COMPARTMENT AND ONE OR MORE CATALYTIC REACTION CHAMBERS OPERATING ON FEED GAS PREHEATED WITHIN SAID COMPARTMENT TO REACTION TEMPERATURE. AN ARRANGEMENT IS DESCRIBED WHEREBY A PORTION OF THE HOT GAS IN THE BOILER SECTION IS MIXED WITH THE UNCONDENSED GAS FROM THE DISCHARGE END OF THE CONDENSING SECTION TO FORM A FEED GAS AT THE PROPER TEMPERATURE FOR THE REACTOR.

Nov. 30, 1971 J. w. PALM 3,623,845

PACKAGE SULFUR PLANT Filed Dec 4 1969 5 -Sheet 1 FIG. I

INVENTOR.

OHN W. PALM BY z 1%) c A T TORNE Y 1971 J. w. PALM 3,623,845

PACKAGE SULFUR PLANT Filed Dec. 4, 1969 5 Sheets-Sheet 2 FIG. 7

INVENTOR.

JOHN w. PALM c147 ATTO//VEY Nov. 30, 1971 J. w. PALM 3,623345 PACKAGE SULFUR PLANT Filed Dec. 4, 19 9 5 Sheets-Sheet 3 I J LL! LLI J INVENTOR.

JOHN w. PALM A TTORNE Y Nov. 30, 1971 J. w. PALM 3,623,845

PACKAGE SULFUR PLANT 5 Sheets-Sheet 4. Filed Dec. 4, 1969 FIG. 5

IIIIIIII FIG.4

INVENTOR. JOHN W. PALM A TTORNE Y Nov. 30, 1971 J. w. PALM 3,623,845

PACKAGE SULFUR PLANT Filed Dec. 4, 1 69 5 Sheets-Sheet 5 INVENTOR.

JOHN W. PALM ATTORNEY United States Patent O "ice 3,623,845 PACKAGE SULFUR PLANT John W. Palm, Tulsa, Okla, assignor to Amoco Production Company Filed Dec. 4, 1969, Ser. No. 882,072 Int. Cl. B01j 9/04; C011 7/04; F27b 19/02 US. Cl. 23-262 9 Claims ABSTRACT OF THE DISCLOSURE A compact apparatus free from external piping is described having within a single elongated shell a boiler and condenser sections within a single compartment and one or more catalytic reaction chambers operating on feed gas preheated within said compartment to reaction temperature. An arrangement is described whereby a portion of the hot gas in the boiler section is mixed with the uncondensed gas from the discharge end of the condensing section to form a feed gas at the proper temperature for the reactor.

SPECIFICATION The present invention relates to a novel apparatus for the production of free sulfur from hydrogen sulfide. More particularly, it is concerned with a compact plant design omitting much of the external piping ordinarily required, and which is adapted to be shipped to the site of use in assembled form, skid mounted.

BACKGROUND OF THE INVENTION Compact or package sulfur recovery plants have been employed for a number of years and are well suited to handle acid gas streams large enough to yield 50-60 long tons of sulfur per day. Typical of such plants is the one described and claimed in Webb US. Pat. 2,939,769. This particular design has been widely used with considerable success. However, it employs a substantial amount of external piping which even though installed so that liquid sulfur will drain therefrom, still can present a problem in the event of an unanticipated shut-down during cold weather. Also, plants of this type if shipped overseas generally have to be transported in disassembled form and then assembled at the plant site requiring skilled labor which sometimes is in short supply.

DESCRIPTION OF THE INVENTION AND THE DRAWINGS The apparatus of my invention has none of the above mentioned disadvantages as may be seen from reference to the following drawings, wherein:

FIG. 1 is a perspective view of a sulfur plant embodying the concept of my invention;

FIG. 2 is a perspective view of the front portion of the same plant shown in FIG. 1 with the shell of insulation cut away;

FIG. 3 is a vertical sectional view of the plant shown in FIG. 1;

FIG. 4 is a view taken along line 44 of the plant illustrated in FIG. 1;

FIG. 5 is a view of FIG. 1 taken along line 5-5;

FIG. 6 is a fragmentary perspective view illustrating the arrangement of the catalyst beds, the piping to and from said beds, and the manner in which such piping is connected to the condenser and catalyst sections; and

FIG. 7 is a detailed drawing illustrating one design of reheat gas valve, shown generally as 27 in FIG. 3, that may be used to regulate the temperature of the feed gas.

Similar reference characters refer to similar parts throughout the several views of the drawings and the description.

Patented Nov. 30, 1971 Broadly, my invention contemplates placement of an entire sulfur plantfurnace, reactors and condenserswithin a single enclosed elongated shell. This design is made possible primarily through a modification of the boiler and condensing sections so that gas leaving a condenser is fed to a catalytic reactor by flowing inside a conduit which passes through the tubesheets of the boiler and condensing sections. Another feature of this compact design is modification of the boiler section so that a part of the hot gas in the boiler can be withdrawn therefrom and used as reheat gas for the uncondensed gases making up the feed stream to the reactors. The novel feature about such design is that the withdrawal of the reheat gas from the boiler section and the reheating of the feed gas occur entirely within the apparatus designated as the combination furnace, boiler and condensing sections. Moreover, these operations as well as delivery of the preheated feed gas to the catalytic reactor occur entirely within the single enclosed elongated shell. This feature not only saves a substantial amount of external piping, but makes the overall plant much more compact and easier to mount on skids to ship in assemled form as a complete unit.

My invention will be further illustrated by reference to FIGS. 1, 2, 3 and 4, wherein a sulfur plant 2 comprises an elongated metal shell 3 having an outer covering of insulation 7. The equipment is supported by skid 9. Part of the metal shell, 3, is removable for access to the internal piping. Within shell 3 the plant is divided into three principal sections: a boiler section 8, condensing sections 10, and reactor section 12. The boiler section includes a fire tube 14 with an acid gas line 13 and a combustion air line 15, return bend or second pass tubes 16, and third pass tubes 18. At the front end of third pass tubes 18 are lines 20 and 21 which take a portion of the hot gases in tubes 18 and transfer them to chambers 22 and 50, thence to feed lines 24 and 25 via adjustable valves 26 and 27. In this description only valve 27 is shown and referred to in detail in FIG. 7, partly because the drawings and disclosure would be unduly complicated by further reference to valve 26, and also for the reason that these valves are identical. Hence a description of both is considered unnecessary. Valve 27 comprises an annular seat 28 held in supporting ring 30 by means of plastic or castable refractory 32. This assembly is mounted on tubesheet 31. The flow of gas from lines 20 and 21 into feed lines 24 and 25 is controlled by the position of valve head 34 with respect to seat 28. Both valve head 34 and seat 28 are ceramic coated to withstand the 1200 F. reheat gas. It will be apparent that lines 20 and 21 need not necessarily be located on third pass tubes 18 but, if desired, may take the reheat gas from tubes 16 or even fire tube 14. The volume of reheat gas employed can be controlled by regulating the flow thereof through lines 20 and 21 by means of valves 26 and 27. Valve stem 36 extends up through a packing gland 40 in the bend of feed line 25.

Beneath fire tube 14 is another group of tubes 42 which take product gas from an upstream reactor, condense the sulfur to liquid form, and discharge it together with uncondensed gas into chamber 44. Liquid product sulfur is removed therefrom via line 46 and uncondensed gas is discharged into vent stack 48. The entire assembly of condensing sections and the boiler section referred to above are of course immersed in water during operation. Lines 49 and 51 afiixed to chambers 22 and 50 serve to drain liquid sulfur flowing into said chambers via tubes 52 and 54.

FIG. 6 shows rear side of the condensing and boiler sections and the relation thereof to reactors 56 and 68. At the back or rear side of the condensing section formed by tubes 42 is a chamber 62. Similarly chambers 64 and 66 are located at the rear of the condensing sections and 3 communicate separately with tubes 52 and 54, respectively.

Feed lines 24 and 25 pass through conduits 25a and 27a respectively which are sealed to the tube sheets 31 and 31a. This novel arrangement prevents direct contact of pipes 24 and 25 with the water within the boiler, which would cause undesired cooling.

Feed line 24 is joined to reactor 68 (reactor No. 1) by means of a flanged connection while feed line 25 extends to the top of reactor 56 (reactor No. 2), both being filled with catalyst 58 resting on supports 60. Manways 72 and 74 communicate with reactors 68 and 56, respectively, so that the catalyst can be removed from and charged to the catalyst chambers when necessary. Product gas lines 76 and 78 connect reactors 68 and 56 with chambers 66 and 62.

In operation of the above described apparatus, acid gas and air with a molar hydrogen sulfide-oxygen ratio of about 2:1 are introduced into the fire tube 14 via line 13 and line 15, respectively. This mixture is burned in tube 14 at a flame temperature of the order of about 2000 to about 2500 P. where approximately one-third of the H S is oxidized to S Also, in the fire tube, some of the S0 thus formed reacts noncatalytically with the H to produce free sulfur. The resulting mixture of H 8, 50; and free sulfur vapors then flows through second and third pass tubes 16 and 18 with the bulk of this mixture emerging into chamber 64 where it is forced back through cooling tubes 52. As these cooled gases enter chamber 22, liquid sulfur accumulates therein and is withdrawn to storage by means of line 49. The uncondensed, cooled gases, now containing primarily H 8, S0 water, nitrogen and carbon dioxide, are then preheated to reaction temperature, e.g., 425 to 450 F., with hot gas bypassed through lines 20 and 21 and valves 26 and 27. The position of valve head 34 with respect to valve seat 28 may be controlled manually by manipulation of stem 36. Observation of the temperature of the feed gas to reactors 68 and 56 by means of thermocouples 69 and 71 determines whether the flow of hot gas through the aforesaid valves is to be increased or decreased.

Considering now the operation of the first reactor 68, feed gas at about 425 F. flows through line 24 into the reactor and contacts catalyst 58. Hot product gases at about 550 to 575 F. are withdrawn at the base of the reactor through line 76. This gas is transferred to chamber 66 where it enters tubes 54 and the free sulfur vapors therein are condensed to liquid. The resulting product sulfur is collected in chamber 50 from which it is re moved to storage by means of line 51. The uncondensed cooled gas containing unreacted H S and S0 is then mixed with sulficient reheat gas coming from line 21 to increase the temperature of the resulting mixture to about 450 F. and thereafter the preheated reaction mixture is transferred to catalytic reactor 56 through line 25. Further conversion of the H 3 and S0 to free sulfur is effected in the catalytic reaction zone of reactor 56 and the effluent withdrawn at a temperature of about 450 to 500 F. This stream is now lean in H S and S0 and is taken to chamber 62 by means of line 78 where the free sulfur in said stream is condensed in tubes 42. Liquid sulfur is discharged from tubes 42 into chamber 44 from which it is then taken to storage through line 46. The unreacted gases are removed from chamber 44 and fiow through line 48 which may serve either as a vent stack or as a conduit to an appropriate incinerator, not shown.

Normally in a sulfur plant of the so-called straight through type, liquid sulfur is condensed from the boiler eflluent gas and the uncondensed vapor is reheated and sent to a downstream catalytic reactor. However, in a plant of the split flow type, sulfur is not condensed from the vapor which flows from the last boiler section to the first catalytic reactor. In the latter case the combustion products from the burner are cooled in a first boiler section, most of the eflluent therefrom is cooled in a second boiler section, a portion of the effluent from the first boiler section mixed with the effluent from the second boiler section, then this mixture is combined with the acid gas which was bypassed around the burner and sent on to the catalytic reactor. My novel arrangement can be used. to effect the desired heating of the second boiler pass effluent and delivery of feed gas to the reactor in this type of plant.

It will be apparent to one skilled in the art that many variations of sulfur plant design can be employed using the principles of this invention.

While my design is particularly applicable to sour gas sources which provide from about 10 to 50 tons of sulfur per day, the principles employed herein can be used in larger package plants which may include sulfur recovery units in whidh the reactors are not enclosed in the same vessel with the boiler and condensing sections. For example, individual pieces of equipment can be placed endto-end or side-by-side and external connecting piping can be minimized by using the principles of my invention. Likewise, it is to be understood that although I have described my invention in terms of a two reactor unit, the principles of my invention may be employed with equal advantage to plants containing one reactor or more than two reactors. Adaptation to a plant containing only one reactor is readily effected merely by omitting condenser tubes 42 and directing all reactor effluent to chamber 66.

I claim:

1. In an apparatus for the conversion of hydrogen sulfide to free sulfur, the combination comprising:

an elongated shell having therein a compartmented section containing a first and second series of tubes defining first and second condensing sections,

a third series of tubes within said compartmented section defining a boiler section including a combustion chamber, the latter being in communication with the first condensing section,

means for injecting air and hydrogen sulfide into said combustion chamber,

a conduit 1) placing said boiler section is communication with the discharge end of the first condensing section,

means for controlling the flow capacity of conduit a conduit (2) communicating with the discharge end of the first condensing section and with the exterior of said compartmented section,

a chamber outside of said compartmented section in direct flow communication with the upstream end of said second condensing section, and

a gas-liquid disengaging means at the discharge end of said second condensing section whereby the second condensing section is placed in non-communicating relatioship with the boiler section within said compartmented section.

2. The apparatus of claim 1 wherein there is provided a chamber housing the discharge end of the first condensing section and said means for controlling the flow capacity of conduit (1).

3. In an apparatus for the conversion of hydrogen sulfide to free sulfur, the combination comprising an elongated shell having therein a compartmented section containing a first series of tubes defining a boiler section including a combustion chamber, and a second and third series of tubes defining first and second condensing sections, said boiler section being in direct communication with said first section,

means for injecting air and hydrogen sulfide into said combustion chamber,

a catalytic reaction chamber outside of said compartmented section and serially arranged within said shell with reference to said boiler and condensing sections,

a conduit (1) partially within said compartmented section joinin said boiler section to the discharge end of said first section,

means for controlling the fiow of gas through conduit (1),

a conduit (2) partially Within said compartmented section communicating with the discharge end of said first condensing section and with said reaction chamber,

a conduit (3) joining the elfiuent side of said reaction chamber with the upstream end of said second condensing section, and

a gas-liquid disengaging means at the discharge end of said second section.

4. The apparatus of claim 3 wherein said condensing sections are vertically disposed with respect to said boiler section.

5. In an apparatus for the conversion of H 5 to free sulfur, the combination comprising an elongated shell having therein a compartmented section containing a boiler section, including a combustion chamber, and first, second and third condensing sections, and first and second catalytic reaction chambers within said shell but outside of said compartment and serially arranged with respect to said boiler and condensing sections, said boiler section being in communication with the first condensing section,

means for injecting air and hydrogen sulfide into said combustion chamber,

means (1) at the discharge end of said first section and cooperating with said boiler section for heating uncondensed gas from said first section,

means partially within said compartmented section for transferring the resulting heated gas to said first reaction chamber outside of said compartmented section but within said shell,

a conduit joining the efiluent side of said first reaction chamber with the upstream end of said second condensing section,

means (2) at the discharge end of said second section and cooperating with said boiler section for heating uncondensed gas from said second section,

means partially Within said compartmented section for transferring the resulting heated gas to said second reaction chamber outside of said compartmented section but within said shell,

a conduit joining the effiuent side of said second reaction chamber with said third condensing section, and

means at the discharge end of said third section for 6 disengaging liquid product sulfur from uncondensed gas. 6. The apparatus of claim 5 wherein there are provided separate chambers housing the discharge ends of the first and second condensing sections and a flow control device for each of means (1) and (2).

7. In an apparatus for conversion of H 5 to free sulfur, the combination comprising an elongated shell having therein a compartmented section containing a boiler section including a combustion chamber, and first, second and third condensing sections, said boiler section being in communication With said first condensing section,

means for injecting air and hydrogen sulfide into said combustion chamber,

first and second catalytic reaction chambers Within said shell but outside of said compartmented section and serially arranged with respect to said boiler and said condensing sections,

means partially within said compartmented section for transferring uncondensed vapor from the discharge end of said first condensing section to said first reaction chamber, and

means partially within said compartmented section for transferring uncondensed vapor from the discharge end of said second condensing section to said second reaction chamber, and a conduit joining the efiiuent side of said second chamber With said third condensing section.

8. The apparatus of claim 7 wherein separate means are provided Within said shell for preheating the vapor from said first condensing section and for preheating the vapor from said second condensing section.

9. The apparatus of claim 7 wherein means Within said shell is provided for transferring effluent from said first reaction chamber to said second condensing section, and wherein means within said shell is provided for transferring effluent from said second reaction chamber to said third condensing section.

References Cited UNITED STATES PATENTS 3,057,698 10/1962 Grekel et al. 23262 2,939,769 6/1960 Webb 23--262 2,834,655 5/1958 Chute et a1. 23277 JAMES H. TAYMAN, JR., Primary Examiner US Cl. X.R.

23225 P, 228 K, 277 R; l22--135 A, 149 

